Yeah, this weekend is looking wet for Texas

Posted by Eric Berger at 1:25 PM on August 22, 2017

Until the remnants of Tropical Storm Harvey are no longer a threat to Texas, we’ll be posting multiple times a day on this site to provide the best available information. Unfortunately, after looking at the latest model data we continue to be concerned about the potential for this tropical system to bring heavy rains to the Texas coast and some inland areas this weekend, and early next week.

As of Tuesday afternoon, the remnants of Harvey are crossing the Yucatan Peninsula, and it appears almost certain that the storm will re-form over the southern Gulf of Mexico during the next 24 to 48 hours.

As of Tuesday afternoon Harvey had not re-formed. Yet. (NOAA)

The forecast models suggest the storm will then move toward the northwest, and come ashore somewhere on Friday(ish) between Brownsville, at the southern end of Texas, and Freeport, which is just down the coast from Galveston. This afternoon, NOAA’s G-IV Hurricane Hunter Jet will fly around the remnants of Harvey, and this should provide useful information that will improve forecast model output tonight, and especially on Wednesday. But frankly, our biggest concern is not where undead Harvey makes landfall (rain, not winds, are most likely the primary threat here), but rather what happens after the storm moves inland. This is because the upper-air pattern later this week and weekend is such that there will be little to steer the movement of the system, and therefore it may wobble around. When you have a tropical system near the warm, moist Gulf of Mexico, this is a bad thing because it means rainfall. Potentially a lot of rainfall.

A ramblin’ man

For example, here’s a plot I made of the tropical low locations forecast by the 12z GFS model, which brings a tropical storm near the Texas coast on Friday. And then, well, here you go:

After Harvey moves inland on Friday, per the GFS, the steering forces disappear. (Space City Weather)

I post this not because you should take the track above as gospel—it is far from it. Rather, the model is illustrative of the fact that this is a tropical system that could very well move inland into Texas somewhere along the coast, more or less stall, and drop 10 to 15 inches of rain (or more) on someone’s head over a two or three day period. Widespread areas may see 4 to 8 inches. I’m not saying this is a repeat of Tropical Storm Allison, as that would be irresponsible. But these kinds of slow moving systems are the ones that often produce widespread flooding.

The next question is, where will the heaviest rainfall occur? Frankly, there is no good answer to that right now. The data gathered by the Hurricane Hunter today will help, so hopefully by Wednesday we should have a slightly better idea. For example, a landfall near Brownsville would be a lot better for Houston than one near Corpus Christi.

What you should know now is that there is the potential for a major rainfall event in Texas this weekend, including possibly the Houston area. Most likely, this will occur sometime on Saturday, Sunday, or Monday. Secondarily, we will be concerned about storm surge and winds if Harvey becomes a strong tropical storm or modest hurricane, but those seem lesser threats at this time.

Armando D.

Thank you Eric. I just was able to calm my dear Fulgencio through the eclipse and now that is believes the sun is really back I will now have to comfort him to not worry about potential floods yet. We eagerly await your next report!

Jason

I love the absence of doom-casting here – its tiring to hear ridiculous “sky is falling” statements from coworkers and Channel 9 when a storm is more than 48 hours out and the track still has huge error bars on it.

I did a safety moment today that was “don’t get scared, just start paying attention” about this storm – Thanks Eric

Chris Villalobos

Chuck

Or buy flood insurance. I’m not in a 100 year flood zone, but buy it anyway. Upstream development that changes land elevation, thus changing storm water runoff pattern it causes supposedly violates State law. But tell that to people in western parts of Houston near Hwy 6 that never flooded before.

Chuck

Well after Rita, the TX Legislature and Public Utilities Commission allowed both Centerpoint and Entergy to add small charges to everyone’s monthly bill called HRC / SRC. The Hurricane Reconstruction Costs (HRC) rider has been a part of customer bills since 2007. The HRC rider was implemented to support the recovery of costs incurred as a result of restoration efforts after Hurricane Rita. The System Restoration Costs (SRC) rider has been a part of customer bills since 2009. The SRC rider was implemented to support the recovery of costs incurred as a result of restoration efforts after Hurricanes Ike and Gustav. They also are supposed to “harden” the transmission and distribution system. I have a presentation made by Entergy in April 2009 covering hardening transmission and distribution systems to better resist wind and flood damage. It’s a pretty technical, cost – benefit analysis, and if you want it, send me an email at [email protected]

Eric Berger

Andrew Cashion

Eric, I’m heading to Leakey area north of Uvalde this weekend. If the storm tracks closer to making landfall near Brownsville, is Leakey subject to heavy rains? We’re staying on the Frio River, but I wouldn’t imagine there would be enough rain upstream to cause the river to flood by Sunday morning. Appreciate any insight!

Eric Berger

Michelle

Now that so many inland Houston neighborhoods and homes have flooded just from spring rainstorms, do you think those areas could ever be deemed an “evacuation zone”? I guess I am thinking of those areas along the bayous and creeks that are well inland and not among the coast (particularly Northwest Houston). I know evacuation zones zones are for wind and storm surge, just curious as Houston is so prone to flooding.

Beating a dead horse

MEC

The majority of people that evacuated during Ike that lived in Katy most likely don’t live there anymore. Besides, a fresh new way of expats will have arrived & having never faced a TS will be worried. It is understandable unless you have grown up on the gulf.

Those that remember Allison are concerned over this even just because of the amounts of rain.

Chuck

Live in The Woodlands, house not in 100 year flood zone and never flooded. However, had to install some drains in my back yard to clear the water to the street. AND, I’ve bought flood insurance ever since Allison. Cost a few $, but buys peace of mind. Hope I never need it, but I just renewed for another year. NOTE: YOUR HOMEOWNERS POLICY DOES NOT COVER “RISING WATER!”

Eric Berger

Kel

We have a cruise booked to depart Sat in Galevston. Carinval hasn’t canceled. We will be putting our car in a parking garage upper floor while away. Not concerned regarding continued rain. Just curious a good time to get to Galevston on Friday, park the car in the garage and get to hotel? Getting the car into the parking garage is the main thing. Does Galveston island flood easily? Should arriving around 3 or 4 pm Sat be ok?